Systems and Methods for Plugging an Oil Well

ABSTRACT

A plug assembly for opening a subterranean wellbore comprises a tubular housing and a first frangible element comprising an activation component. The first frangible element has a first orifice in an uphole side that extends at least partially through the first frangible element. The activation component initially seals the first orifice to prevent fluid communication from the uphole side of the first frangible element with the first orifice. After the activation component is activated, fluid communication is enabled from the uphole side of the first frangible element with the first orifice.

TECHNICAL FIELD

The present disclosure relates to a holding and crushing device for a plug device in hydrocarbon wells, the plug device comprising a frangible element and a support media.

BACKGROUND

For a variety of oil well drilling operations, a plug is used in a tool string that is capable of being opened in a controlled manner. An example of such a plug is a flotation plug used to float casing into highly-deviated or horizontal wellbores. In such applications, the plug can be installed in the tool string as the tool string is run downhole.

Existing barrier plugs and similar devices are brought into an open or plugged state by a mechanical or hydraulic translation of an activation signal and/or force from the upper side of the plug to the lower side of the plug. This mechanical or hydraulic translation takes place though a channel or bore that bypasses the sealing devices of the plug. Such configurations comprise many parts and potential points of failure, in the form of sleeves, seals, rings etc. Also, configurations based on bypass channels and bores are inherently vulnerable, since they provide potential paths of fluid loss, pressure drops, and other forms of leakage. In addition, such complicated and vulnerable plug arrangements are dependent on tight tolerances and movement of several parts.

In order to reduce or eliminate the above mentioned disadvantages of known techniques, there is a need for an improved plug arrangement comprising a frangible barrier material. Particularly, there is a need for a plug arrangement comprising an activation system that is simple to manufacture, and reliably opens when triggered. While some embodiments of the present disclosure are applicable to barrier plugs, the same mechanisms described herein are also useful in other applications in hydrocarbon wells where a plugging device is needed to separate and then controllably open two regions.

SUMMARY

It is an object of the present disclosure to mitigate, alleviate or eliminate one or more of the above-identified deficiencies and disadvantages.

In one aspect a plug assembly for opening a subterranean wellbore is disclosed. The plug assembly may include a tubular housing having an uphole end and a downhole end and configured for internal fluid communication from the uphole end to the downhole end, and a first frangible element disposed in the tubular housing, the first frangible element having a first orifice in an uphole side of the first frangible element. In the plug assembly, the first orifice may extend at least partially through the first frangible element. The plug assembly may further include an activation component configured for sealing the first orifice and located at the uphole side of the first frangible element. In the plug assembly, the activation component may initially seal the first orifice to prevent fluid communication from the uphole side of the first frangible element with the first orifice. After the activation component is activated, the activation component may enable fluid communication from the uphole side of the first frangible element with the first orifice.

In any of the disclosed embodiments of the plug assembly, the first frangible element may be a glass disc.

In any of the disclosed embodiments of the plug assembly, the first orifice may extend completely through the first frangible element.

In any of the disclosed embodiments of the plug assembly, the first orifice may be located off-center of the first frangible element.

In any of the disclosed embodiments of the plug assembly, the activation component may be a burst disc.

In any of the disclosed embodiments of the plug assembly, the first frangible element may be disposed on a beveled seat in the tubular housing.

In any of the disclosed embodiments, the plug assembly may further include first support media located in the tubular housing downhole from the first frangible element. In the plug assembly, an uphole side of the first support media may be in physical contact with a downhole side of the first frangible element, while the first support media may further include a first fluid passageway through the first support media, and the first support media may be configured for disintegrating when a fluid passes through the first fluid passageway.

In any of the disclosed embodiments of the plug assembly, the first support media may be housed in a first tapered cavity in the tubular housing, while the first support media may be correspondingly tapered to the first tapered cavity to enable detention of the first support media in the first tapered cavity.

In any of the disclosed embodiments, the plug assembly may further include a second frangible element located on a beveled seat formed in the tubular housing. In the plug assembly, the second frangible element may be in physical contact with a downhole surface of the first frangible element.

In any of the disclosed embodiments of the plug assembly, the second frangible element may include a second orifice that extends partially through the second frangible element. In any of the disclosed embodiments of the plug assembly, the second orifice may be aligned with the first orifice. In any of the disclosed embodiments of the plug assembly, the second frangible element may include a glass disc.

In any of the disclosed embodiments, the plug assembly may further include a conformal layer located between the first frangible element and the second frangible element. In the plug assembly, conformal layer may maintain physical contact with both the first frangible element and the second frangible element.

In any of the disclosed embodiments, the plug assembly may further include second support media located in the tubular housing downhole from the first support media. In the plug assembly, an uphole side of the second support media may be in physical contact with a downhole side of the first support media. The plug assembly may further include a third frangible element located in the tubular housing and enabled to seal the tubular housing to prevent the internal fluid communication, the third frangible element having a third orifice in an uphole side of the third frangible element. In the plug assembly, the third orifice may extend partially through the third frangible element, while an uphole side of the third frangible element may be in physical contact with a downhole side of the second support media.

In any of the disclosed embodiments of the plug assembly, the second support media may be housed in a second tapered cavity in the tubular housing. In the plug assembly, the second support media is correspondingly tapered to the second tapered cavity to enable detention of the second support media in the second tapered cavity, while the second tapered cavity may be tapered in an opposite orientation to the first tapered cavity.

In another aspect, a method of enabling fluid communication through a subterranean wellbore using a plug assembly is disclosed. The method may begin after installing a plug assembly in a subterranean wellbore, the plug assembly being installed in an initial condition that seals the subterranean wellbore to prevent fluid communication through the subterranean wellbore. Responsive to an increase in pressure of a fluid above a threshold pressure value at an uphole side of the plug assembly, the method may include activating an activation component located in a tubular housing of the plug assembly, the tubular housing enabling fluid communication with the fluid and the activation component. Upon activating the activation component, the method may include subjecting a first orifice extending at least partially through a first frangible element to the pressure from the fluid. In the method, prior to the activating, the activation component may be configured to seal the first orifice from the fluid. Responsive to the pressure of the fluid impacting the first orifice, the method may include causing the fluid to penetrate the first frangible element at the first orifice, such that the first frangible element is shattered.

In any of the disclosed embodiments of the method, the activation component and the first orifice may be centered on the tubular housing.

In any of the disclosed embodiments of the method, the activation component and the first orifice may be located eccentrically with respect to the tubular housing.

In any of the disclosed embodiments of the method, the first frangible element may be a glass disc.

In any of the disclosed embodiments of the method, the activation component may be a burst disc.

In any of the disclosed embodiments of the method, the first frangible element may be disposed on a beveled seat in the tubular housing.?

In any of the disclosed embodiments, the method may further include causing the fluid under the pressure to flow through a first fluid passageway of first support media in physical contact with the first frangible element. In the method, the first fluid passageway may be aligned with the first orifice, while the fluid may disintegrate the first support media until the first support media is flushed downhole by the fluid. After the first support media is removed, the method may include flushing the first frangible element downhole by the fluid, while the tubular housing may be fully opened to enable the fluid communication through the tubular housing.

In any of the disclosed embodiments of the method, the first support media may be housed in a first tapered cavity in the tubular housing, while the first support media may be correspondingly tapered to the first tapered cavity to enable detention of the first support media in the first tapered cavity.

In any of the disclosed embodiments, the method may further include causing the fluid under the pressure to impact a second frangible element in physical contact with the first frangible element. In the method, fluid may impact the second frangible element at the location of the first orifice, and the fluid may disintegrate the second frangible element until the second frangible element is flushed downhole by the fluid. After the second frangible element is removed, the method may include flushing the first frangible element downhole by the fluid, while the tubular housing may be fully opened to enable the fluid communication through the subterranean wellbore.

In any of the disclosed embodiments of the method, the second frangible element may include a second orifice that extends partially through the second frangible element, while the second orifice may be aligned with the first orifice.

In any of the disclosed embodiments of the method, the second frangible element may be a glass disc seated on a beveled seat formed in the tubular housing.

In any of the disclosed embodiments, the method may further include causing the fluid under the pressure to flow through a second fluid passageway of second support media in physical contact with the first support media, while the second fluid passageway may be in fluid communication with the first fluid passageway. Upon the fluid under the pressure flowing through the second fluid passageway, the method may include subjecting a second orifice extending partially through a second frangible element to the pressure from the fluid, where the second frangible element may be shattered and flushed downhole by the fluid. Responsive to the second frangible element being shattered, the method may include causing the fluid under pressure to disintegrate the second support media and the first support media until the second support media and the first support media are flushed downhole by the fluid. After the second support media and the first support media are removed, the method may include flushing the first frangible element downhole by the fluid, such that the tubular housing may be fully opened to enable the fluid communication through the subterranean wellbore.

In any of the disclosed embodiments of the method, the second support media may be housed in a second tapered cavity in the tubular housing, while the second support media may be correspondingly tapered to the second tapered cavity to enable detention of the second support media in the second tapered cavity, and the second tapered cavity may be tapered in an opposite orientation to the first tapered cavity.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A depicts a plug in accordance with embodiments having a frangible element with an orifice passing completely through the frangible element, sealed to the casing by an O-ring disposed in a recess in the casing, and supported by support media.

FIG. 1B is an inset drawing of the plug of FIG. 1A, depicting the activation component of the plug.

FIG. 1C depicts the plug of FIG. 1A after the activation component has been activated, the frangible element has been shattered, and the support media is partially eroded.

FIG. 1D depicts the plug of FIG. 1A after the plug has been fully opened.

FIG. 2A depicts a plug in accordance with embodiments having a frangible element with an orifice passing completely through the frangible element, sealed to the casing by an O-ring disposed in a recess in the frangible element, and supported by support media.

FIG. 2B is an inset drawing of the plug of FIG. 2A, depicting the activation component of the plug.

FIG. 2C depicts the plug of FIG. 2A after the activation component has been activated, the frangible element has been shattered, and the support media is partially eroded.

FIG. 2D depicts the plug of FIG. 2A after the plug has been fully opened.

FIG. 3A depicts a plug in accordance with embodiments having a frangible element with an orifice passing partially through the frangible element, sealed to the casing by an O-ring disposed in a recess in the casing, and supported by support media.

FIG. 3B is an inset drawing of the plug of FIG. 3A, depicting the activation component of the plug.

FIG. 3C depicts the plug of FIG. 3A after the activation component has been activated, the frangible element has been shattered, and the support media is partially eroded.

FIG. 3D depicts the plug of FIG. 3A after the plug has been fully opened.

FIG. 4A depicts a plug in accordance with embodiments configured to resist pressure from both directions, having two frangible elements with orifices passing partially through the frangible elements, with an activation component in the frangible element on the uphole side of the plug, sealed to the casing by an O-ring disposed in a recess in the casing, and supported by two support media.

FIG. 4B is an inset drawing of the plug of FIG. 4A, depicting the activation component of the plug.

FIG. 4C depicts the plug of FIG. 4A after the activation component has been activated, and the frangible elements have been shattered.

FIG. 4D depicts the plug of FIG. 4A after the activation component has been activated, the frangible elements have been shattered, the downhole frangible element has been flushed away, and the support media are partially eroded.

FIG. 4E depicts the plug of FIG. 4A after the plug has been fully opened.

FIG. 5A depicts a plug in accordance with embodiments having a frangible element with an orifice passing partially through the frangible element, disposed on a beveled seat, and an activation component.

FIG. 5B is an inset drawing of the plug of FIG. 5A, depicting the activation component of the plug.

FIG. 5C depicts the plug of FIG. 5A after the activation component has been activated, and the frangible element has been fractured.

FIG. 5D depicts the plug of FIG. 5A after the plug has been fully opened.

FIG. 6A depicts a plug in accordance with embodiments having a frangible element with an orifice passing partially through the frangible element, and located off-center of the frangible element, disposed on a beveled seat, and an activation component.

FIG. 6B is an inset drawing of the plug of FIG. 6A, depicting the activation component of the plug.

FIG. 7A depicts a plug in accordance with embodiments having two frangible elements, each with an orifice passing partially through the frangible element, the downhole frangible element disposed on a beveled seat, and an activation component.

FIG. 7B is an inset drawing of the plug of FIG. 7A, depicting the activation component of the plug.

FIG. 7C depicts the plug of FIG. 7A after the activation component has been activated, and the uphole frangible element has been fractured.

FIG. 7D depicts the plug of FIG. 7A after both frangible elements have been fractured.

FIG. 7E depicts the plug of FIG. 7A after the plug has been fully opened.

FIG. 8A depicts a plug in accordance with embodiments having two frangible elements, having a conformal layer between the first and second frangible elements.

FIG. 8B is an inset drawing of the plug of FIG. 8A, depicting the activation component of the plug.

FIG. 9A depicts a plug in accordance with embodiments having two frangible elements, the uphole frangible element having an orifice passing partially through the frangible element, and the downhole frangible element having no orifice, and disposed on a beveled seat, and an activation component.

FIG. 9B is an inset drawing of the plug of FIG. 9A, depicting the activation component of the plug.

FIG. 9C depicts the plug of FIG. 9A after the activation component has been activated, and the downhole frangible element has been fractured.

FIG. 9D depicts the plug of FIG. 9A after both frangible elements have been fractured.

FIG. 9E depicts the plug of FIG. 9A after the plug has been fully opened.

FIG. 10A depicts a plug in accordance with embodiments having a frangible element with an orifice passing partially through the frangible element, disposed on a beveled seat, and an activation device, where the activation device includes a dart.

FIG. 10B is an inset drawing of the plug of FIG. 10A, depicting the activation device of the plug.

FIG. 11A depicts a plug in accordance with embodiments having a frangible element with an orifice passing partially through the frangible element, disposed on a beveled seat, and an activation device, where the activation device includes a multi-cycle pressure valve.

FIG. 11B is an inset drawing of the plug of FIG. 11A, depicting the activation device of the plug.

DETAILED DESCRIPTION

The following detailed description is submitted with reference to the accompanying drawings, in which certain example embodiments are shown. There may, however, be other embodied forms and the present disclosure should not be construed as limited to the herein disclosed embodiments. Although example embodiments of the present disclosure are explained in detail, it is to be understood that other embodiments are contemplated within the scope of the disclosure. Accordingly, it is not intended that the present disclosure be limited in its scope to the details of construction and arrangement of components set forth in the following description or illustrated in the drawings. The present disclosure is capable of other embodiments and of being practiced or carried out in various ways.

Throughout this disclosure, a hyphenated form of a reference numeral refers to a specific instance of an element and the un-hyphenated form of the reference numeral refers to the element generically or collectively. Thus, as an example (not shown in the drawings), device “12-1” refers to an instance of a device class, which may be referred to collectively as devices “12” and any one of which may be referred to generically as a device “12”. In the figures and the description, like numerals are intended to represent like elements.

It must also be noted that, as used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Moreover, titles or subtitles may be used in this specification for the convenience of a reader, which have no influence on the scope of the present disclosure.

By “comprising” or “containing” or “including” is meant that at least the named compound, element, particle, or method step is present in the composition or article or method, but does not exclude the presence of other compounds, materials, particles, method steps, even if the other such compounds, material, particles, method steps have the same function as what is named.

In describing example embodiments, terminology will be resorted to for the sake of clarity. It is intended that each term contemplates its broadest meaning and includes all technical equivalents that operate in a similar manner to accomplish a similar purpose. Where a tool, component, or direction is referred to as “uphole,” the term refers to a direction along the course of the wellbore that leads to the surface, and “downhole” refers to a direction along the course of the wellbore that leads to the end of the wellbore furthest from the surface. These terms retain the same meaning, even if the wellbore is highly deviated, or horizontal.

In the following detailed description, references are made to the accompanying drawings that form a part hereof and that show, by way of illustration, specific embodiments or examples. In referring to the drawings, like numerals represent like elements throughout the several figures.

FIG. 1A depicts a plug 100 in accordance with the disclosed technology. The plug consists of a first tubular component 101 having a fluid passageway 102 therethrough and a second tubular component 103, having a second fluid passageway 104 therethrough. The first tubular component 101 and second tubular component 102 are joined together to create the outer casing of the plug 100.

When joined together, the first and second tubular components 101 and 103 can form a cavity having a first recess 105 configured to hold a frangible element 106. In this embodiment, the frangible element 106 has an orifice 107 passing through the frangible element 106.

The first and second tubular components 101 and 103 can also form a second cavity 108 configured to hold a support media 109. The second cavity 108 can be configured to hold the support media 107 by being tapered, as depicted in FIG. 1. The support media 109 is also configured to have a fluid passageway 110 which allows fluid to pass through, and erode or dissolve the support media 109. Numerous other configurations can be used in embodiments to hold the support media, such as molding the support media to have teeth that interlock with teeth machined into one of the first and second tubular components 101 and 103. Any configuration of the second cavity 108 can be used, such that the support media 109 can withstand pressure applied to the surface of the frangible element 106 opposite the support media 109.

The frangible element 106 can be made from a frangible material such that, in the absence of the support media 109, the frangible element 106 breaks into pieces, allowing fluid communication between the fluid passageways between the first and second tubular components 101 and 103. In some embodiments, the frangible material can be glass, ceramics, polymers, or other similar materials. In some embodiments, the frangible material can be configured such that, when it breaks, it breaks into small pieces capable of being circulated out of the wellbore, such as a glass disc having a high internal tension, or a component having pre-scored lines or other indentations to facilitate fragmenting into small pieces. The frangible element 106 is intended to break, or in other words, for at least one fracture to be initiated in the frangible element. In embodiments, this fracture is intended to cause at least a portion of the frangible element 106 to separate and be flushed into the wellbore, allowing fluid to pass through the tubular housing.

The support media 109 can be made from any material capable of being eroded or dissolved by fluid flow through fluid passageway 110. Examples of materials that support media may be comprised of include salt (such as NaCl), hard-pressed sand, magnesium, and other materials capable of dissolution or erosion.

FIG. 1B. depicts an activation component 111 in accordance with embodiments installed in frangible element 106. The activation component 111 seals the orifice 107 of the frangible element 106 to prevent fluid from the uphole direction from entering the orifice 107, and when activated, allows fluid from the uphole direction to enter the orifice 107. The activation component 111 can be a pressure-activated valve that seals the orifice in the frangible element 106. The pressure-activated valve can be any kind of valve known in the art to trigger when the pressure applied across the valve exceeds a known value. An example of such a pressure-activated valve is a burst disc. Another example of an activation component 111 is a plug made of a dissolvable material. Such an activation component 111 can serve to open the plug as a result of the passage of time, rather than an increase in pressure.

To use plug 100, the plug 100 is installed in a tool string, such as a casing string, drill string, or other similar string of tubulars. The plug 100 provides isolation between the first and second fluid passageways 102 and 104 on either side of the frangible element 106. When the operator wishes to open the plug 100, additional pressure is applied to the uphole surface of frangible element 106 such that the activation component 111 is activated. When the activation component 111 is activated, fluid from the uphole end of the plug 100 is allowed to pass through the orifice 107 to the downhole end of the plug 100. This rapid flow of fluid also passes through fluid passageway 110 through support media 109, and causes the support media 109 to erode and/or dissolve, as depicted in FIG. 1C. Once a sufficient amount of the support media 109 has dissolved such that it can no longer support the frangible element 106, the frangible element 106 breaks, further accelerating the flow of fluid through the plug 100. Once the support media 109 has eroded/dissolved and the frangible element 106 has shattered, the plug is fully opened, as shown in FIG. 1D, allowing further operations to be performed through the opened plug.

FIG. 2A depicts another plug 200 in accordance with embodiments. Plug 200 is similar to plug 100, differing in the configuration of the seal between frangible element and the outer casing. Elements of plug 200 which are similar to plug 100 are depicted with like reference numerals. In the embodiment of FIG. 1A, the O-ring seal 112 around the circumference of frangible element is located in a recess of the outer casing. In the embodiment of FIG. 2A, the O-ring seal 212 is located in a recess around the circumference of the frangible element. FIG. 2B depicts the activation component 111 of plug 200. The plug 200 can be operated in a similar manner as plug 100. FIG. 2C depicts plug 200 after the activation component 111 has been opened, the support media 109 is eroded, and the frangible element 106 is beginning to break. Once the plug 200 is fully opened, the frangible element 106 and support media 109 are flushed through the plug 200, allowing further operations to be performed through the opened plug, as shown in FIG. 2D.

FIG. 3A depicts another plug 300 in accordance with embodiments. Plug 300 is similar to plug 100, differing in the configuration of the frangible element. Elements of plug 300 which are similar to plug 100 are depicted with like reference numerals. In plug 300, a frangible element 306 does not have an orifice that passes completely through frangible element 306. Instead, frangible element 306 has an orifice 307 that does not pass completely through the frangible element 306. In this configuration, the activation component 111 seals the outer surface of the orifice 307. This orifice 307 also creates a weak spot in the frangible element 306. When the activation component 111 is activated, and fluid is allowed to pass into the orifice 307, the fluid pressure applied to the bottom of orifice 307, in the weak spot of frangible element 306, causes the frangible element 306 to break before the fluid reaches the support media 109. In this configuration, the fluid breaking through the frangible element 306 provides an initial fracturing of the frangible element 306, which can facilitate breaking the frangible element 306 into smaller pieces once the support media 109 is eroded. FIG. 3B is an inset drawing of FIG. 3A, and depicts the activation component 111 of plug 300. FIG. 3C depicts plug 300 after the activation component 111 has been opened, the support media 109 is eroded, and the frangible element 306 is beginning to break. Once the plug 300 is fully opened, the frangible element 306 and support media 109 are flushed through the plug 300, allowing further operations to be performed through the opened plug, as shown in FIG. 3D.

FIG. 4A depicts another plug 400 in accordance with embodiments. Plug 400 is similar to plug 300, but is modified to allow the plug to hold pressure from both the uphole and downhole directions. Elements of plug 400 which are similar to plug 100 are depicted with like reference numerals.

Plug 400 is comprised of a sleeve 402 that may be inserted between a first tubular component 101 and a second tubular component 403. The first tubular component 101 and second tubular component 403 are joined together on either end of the sleeve 402 to create the outer casing of the plug 400. In a similar manner as mounted within the tubular component 103 shown in FIG. 1A, the sleeve 402 further comprises a first frangible element 406-1 supported by a first support media 409-1 having a first fluid passageway 410-1 therethrough. The first support media 409-1 is housed in a first cavity 408-1 at an uphole end of the sleeve 402 that is tapered to retain the first support media 409-1. At the uphole end of sleeve 402, a first recess 405-1 may house a first frangible element 406-1 in physical contact with the first support media 409-1.

Further in the embodiment shown in FIG. 4A, the sleeve 402 further comprises a second frangible element 406-2 supported by a second support media 409-2 located uphole of, and in physical contact with the second frangible element 406-2. The second support media 409-2 has a second fluid passageway 410-2 therethrough. The second support media 409-2 is housed in a second cavity 408-2 that is tapered in a reverse manner as first cavity 408-1. The second support media 409-2 is oriented opposite the first support media 409-1, while the first support media 409-1 and the second support media 409-2 are in physical contact at a midpoint of sleeve 402. When both the support media 409 are installed in sleeve 402, the first fluid passageway 410-1 and the second fluid passageway 410-2 are in fluid communication with each other.

When joined together at the uphole end of sleeve 402, the first tubular component 101 and sleeve 402 can form a first cavity having a first recess 405-1 configured to hold the first frangible element 406-1. When joined together at the downhole end of sleeve 402, the second tubular component 403 and sleeve 402 can also form a second cavity having a second recess 405-2 configured to hold the second frangible element 406-2. Similar to plug 300 shown in FIG. 3A, the first frangible element 406-1 has a first orifice 407-1 that does not pass completely through the first frangible element 406-1. In this configuration, the activation component 111 seals the outer surface of the first orifice 407-1. The second frangible element 406-2 can have a second orifice 407-2 in its uphole surface that passes partially through the second frangible element 406-2, creating a weak spot in the second frangible element 406-2. FIG. 4B is an inset drawing of FIG. 4A, and depicts the activation component 111 of plug 400. FIG. 4C depicts the plug 400 after the activation component 111 has been activated. When activation occurs, fluid from the uphole side of the plug 400 is allowed to pass through first fluid passageway 410-1 and then through second fluid passageway 410-2, striking the second frangible element 406-2 at the bottom of the second orifice 407-2 in the second frangible element 406-2, causing the second frangible element 406-2 to break. As depicted in FIG. 4D, once the second frangible element 406-2 is broken, a fluid pathway is opened through the plug 400, allowing fluid from the uphole direction to erode the first and second support media 409. As depicted in FIG. 4D, once the first and second support media 409 are dissolved or eroded away, the first frangible element 406-1 also breaks and is flushed away by the fluid. FIG. 4E depicts the plug 400 once fully opened.

FIG. 5A depicts another plug 500 in accordance with embodiments. Plug 500 omits the support media, and is instead supported by a beveled seat 513 in a tubular component 503. Elements of plug 500 which are similar to plug 300 are depicted with like reference numerals. The frangible element 306 has an orifice 307 passing partially through frangible element 306, and thus, partially through the plug 500, with an activation component 111 installed in the opening of the orifice 307. FIG. 5B depicts the activation component of plug 500. FIG. 5C depicts plug 500 after it has been activated, where fluid from the uphole side of the plug 500 has impacted the bottom of the orifice 307 and caused the frangible element 306 to shatter. FIG. 5D depicts the plug 500 after fluid from the uphole side of the plug 500 has washed away the fragments of the frangible element 306, fully opening the plug.

FIG. 6A depicts another plug 600 in accordance with embodiments. Plug 600 is substantially similar to plug 500, but is modified in that the orifice 307 in the frangible element 306 is not centered in the frangible element 306. Instead, the orifice 307 is offset from the center of frangible element 306, and thus, from the center of plug 600. Elements of plug 600 which are similar to plug 500 are depicted with like reference numerals. This illustrates that the orifice 307 through the frangible element 306, or support media 109 in embodiments, need not be centered in the tubular casing, but can be offset from center, without changing the functionality of plugs in accordance with embodiments. Indeed, plugs with offset orifices, along with offset fluid passageway 110 when present, (in any of the frangible element, support media, or other supporting devices of certain plugs described herein) are within the scope of embodiments contemplated by this disclosure. FIG. 6B depicts the activation component of plug 600.

FIG. 7A depicts another plug 700 in accordance with embodiments. Plug 700 is similar to plugs 500 and 600, but differs in that the first frangible element 306 is seated on a second frangible element 706, which sits on a beveled seat 712. Elements of plug 700 which are similar to plug 500 are depicted with like reference numerals. In this embodiment, both the first and second frangible elements 306, 706 have respective orifices 307, 707 that pass partly through them. FIG. 7B depicts the activation component 111 of plug 700, showing the alignment of the respective orifices 307, 707 of the first and second frangible elements 306, 706. FIG. 7C depicts the plug 700 after the activation component 111 has been activated. First, fluid from the uphole side of the first frangible element 306 strikes the bottom of the first frangible element 306, causing it to break. As depicted in FIG. 7D, once the first frangible element 306 is broken, fluid from the uphole direction can enter the orifice 707 of the second frangible element 706, causing it to break as well. As depicted in FIG. 7E, once both the first and second frangible elements 306, 706 are broken, fluid from the uphole direction can flush the broken fragments of the first and second frangible elements 306, 706 out of the plug 700, resulting in a fully opened plug.

FIG. 8A depicts another plug 800 in accordance with embodiments. Plug 800 is similar to plug 700, but differs in that a conformal layer 814 of material is inserted between the first and second frangible elements. Elements of plug 800 which are similar to plug 700 are depicted with like reference numerals. This conformal layer 814 of material assists in transferring loads applied from the first frangible element 306 to the second frangible element 706. As shown and described, the first and second frangible elements 306, 706 are prone to breaking at the point where they are physically in contact with one another. If the two frangible elements 306, 706 are not carefully manufactured to nearly perfectly rest on one another, point loads can be developed between the two frangible elements 306, 706, which can lead to failure. In plug 700, the interface between the first and second frangible elements 306, 706 are flat surfaces that directly abut each other. If those surfaces are not extremely flat, then any prominences or depressions in the surface can result in point loads that may result in failure. This source of potential failure can be mitigated by manufacturing the first and second frangible elements 306, 706 to tight tolerances, such as by polishing. However, this adds cost and manufacturing time, which may not be desirable.

As an alternative, plug 800 adds a conformal layer 814 of material between the first and second frangible elements 306, 706 that can prevent the formation of point loads, and assists in spreading the load applied to the first frangible element across the entire surface of the second frangible element. The presence of the conformal layer 814 can also increase the total strength of the assembly of the first and second frangible elements 306, 706 to resist pressure, and can increase the consistency of that strength by accommodating manufacturing variation in the contact areas between the first and second frangible elements 306, 706. The conformal layer 814 of material can be conformal such that it substantially fills in the space between the first and second frangible elements. The conformal layer 814 can be made of a single sheet of material or molded component inserted between the two, or can be made of a ductile substance compressed between the first and second frangible elements 306, 706, among other embodiments. This conformal layer 814 can be made of a dissolvable or erodible material, such that, when the plug 800 is opened, the conformal layer 814 is also cleared from the opened plug 800. Conformal layer 814 can be added or used with any plug in accordance with this disclosure where two frangible elements are adjacent or where loads must be transferred from one frangible element to another frangible element.

FIG. 9A depicts another plug 900 in accordance with embodiments. Plug 900 is similar to plug 700, but differs in that the orifice 907 in the first frangible element 306 passes completely through it, and the second frangible element 906 does not have an orifice at all. Elements of plug 900 which are similar to plug 700 are depicted with like reference numerals. In embodiments, the second frangible element 906 can have an orifice that passes partially through the second frangible element. FIG. 9B depicts the activation component 111 of plug 800. When the activation component 111 is activated, fluid from the uphole side of the plug is allowed to pass through the first frangible element 306, striking the second frangible element 906. As depicted in FIG. 9C, this fluid fractures the second frangible element 906, and the continued flow of fluid flushes it away. As depicted in FIG. 9D, with the second frangible element 906 washed away, the first frangible element 306 is freed to slide in the tubular housing in the downhole direction, striking the beveled seat 913 in which the second frangible element 906 was seated. This impact causes the first frangible element 306 to break. As depicted in FIG. 9E, the continued flow of fluid from the uphole direction flushes the broken fragments of the first frangible element 306, resulting in a fully opened plug.

FIG. 10A depicts a plug 1000 in accordance with embodiments, and illustrates an alternative activation method for use with embodiments. Elements of plug 1000 which are similar to plug 500 are depicted with like reference numerals. FIG. 10B shows a detailed drawing of this alternative activation device 1015. In this embodiment, a tube 1016 is installed in the orifice 307 of the frangible element 306, and a dart 1017 is placed in the tube 1015 at the uphole end of the tube 1016. In some embodiments, the tube 1016 and the dart 1017 can be made of a frangible material. An activation component 111 is installed in the uphole end of the tube. When the activation component 111 is opened, fluid from the uphole direction rushes into the tube 1016, accelerating the dart 1017 down the tube, where it impacts the bottom of the orifice 307 of the frangible element 306, causing the frangible element 306 to break. The activation device 1015 depicted in FIG. 10A can be used with other embodiments previously described.

FIG. 11A depicts a plug 1000 in accordance with embodiments, and illustrates another alternative activation method for use with embodiments. Elements of plug 1000 which are similar to plug 500 are depicted with like reference numerals. FIG. 11B shows a detailed drawing of an alternative activation device 1115. In this embodiment, a multi-cycle pressure-activated valve 1116 is installed in the orifice 307 of the frangible element 306. This multi-cycle pressure-activated valve 1116 allows operators to open the wellbore after the activation pressure of the multi-cycle valve 1116 has been exceeded a predetermined number of times. The activation device depicted in FIG. 11A can be used with other embodiments previously described.

The present disclosure is not limited to the embodiments described above. Modifications and variations are possible within the scope of the appended claims. Additionally, variations to the disclosed embodiments can be understood and effected from the drawings, the disclosure, and the appended claims. 

1. A plug assembly for opening a subterranean wellbore, the plug assembly comprising: a tubular housing having an uphole end and a downhole end and configured for internal fluid communication from the uphole end to the downhole end; a first frangible element disposed in the tubular housing, the first frangible element having a first orifice in an uphole side of the first frangible element, wherein the first orifice extends at least partially through the first frangible element; and an activation component configured for sealing the first orifice and located at the uphole side of the first frangible element, wherein the activation component initially seals the first orifice to prevent fluid communication from the uphole side of the first frangible element with the first orifice, and wherein, after the activation component is activated, the activation component enables fluid communication from the uphole side of the first frangible element with the first orifice.
 2. The plug assembly of claim 1, wherein the first frangible element is a glass disc.
 3. The plug assembly of claim 1, wherein the first orifice extends completely through the first frangible element.
 4. The plug assembly of claim 1, wherein the first orifice is located off-center of the first frangible element.
 5. The plug assembly of claim 1, wherein the activation component is a burst disc.
 6. The plug assembly of claim 1, wherein the first frangible element is disposed on a beveled seat in the tubular housing.
 7. The plug assembly of claim 1, further comprising: first support media located in the tubular housing downhole from the first frangible element, wherein an uphole side of the first support media is in physical contact with a downhole side of the first frangible element, wherein the first support media further comprises a first fluid passageway through the first support media, and wherein the first support media is configured for disintegrating when a fluid passes through the first fluid passageway.
 8. The plug assembly of claim 7, wherein the first support media is housed in a first tapered cavity in the tubular housing, and wherein the first support media is correspondingly tapered to the first tapered cavity to enable detention of the first support media in the first tapered cavity.
 9. The plug assembly of claim 1, further comprising: a second frangible element located on a beveled seat formed in the tubular housing, wherein the second frangible element is in physical contact with a downhole surface of the first frangible element.
 10. The plug assembly of claim 9, wherein the second frangible element comprises a second orifice that extends partially through the second frangible element.
 11. The plug assembly of claim 10, wherein the second orifice is aligned with the first orifice.
 12. The plug assembly of claim 9, wherein the second frangible element comprises a glass disc.
 13. The plug assembly of claim 9, further comprising: a conformal layer located between the first frangible element and the second frangible element, wherein the conformal layer maintains physical contact with both the first frangible element and the second frangible element.
 14. The plug assembly of claim 8, further comprising: second support media located in the tubular housing downhole from the first support media, wherein an uphole side of the second support media is in physical contact with a downhole side of the first support media; and a third frangible element located in the tubular housing and enabled to seal the tubular housing to prevent the internal fluid communication, the third frangible element having a third orifice in an uphole side of the third frangible element, wherein the third orifice extends partially through the third frangible element, and wherein an uphole side of the third frangible element is in physical contact with a downhole side of the second support media.
 15. The plug assembly of claim 14, wherein the second support media is housed in a second tapered cavity in the tubular housing, wherein the second support media is correspondingly tapered to the second tapered cavity to enable detention of the second support media in the second tapered cavity, and wherein the second tapered cavity is tapered in an opposite orientation to the first tapered cavity.
 16. A method of enabling fluid communication through a subterranean wellbore using a plug assembly, the method comprising: after installing a plug assembly in a subterranean wellbore, the plug assembly being installed in an initial condition that seals the subterranean wellbore to prevent fluid communication through the subterranean wellbore, the method further comprising: responsive to an increase in pressure of a fluid above a threshold pressure value at an uphole side of the plug assembly, activating an activation component located in a tubular housing of the plug assembly, the tubular housing enabling fluid communication with the fluid and the activation component; upon activating the activation component, subjecting a first orifice extending at least partially through a first frangible element to the pressure from the fluid, wherein prior to the activating, the activation component is configured to seal the first orifice from the fluid; and responsive to the pressure of the fluid impacting the first orifice, causing the fluid to penetrate the first frangible element at the first orifice, wherein the first frangible element is shattered.
 17. The method of claim 16, wherein the activation component and the first orifice are centered on the tubular housing.
 18. The method of claim 16, wherein the activation component and the first orifice are located eccentrically with respect to the tubular housing.
 19. The method of claim 16, wherein the first frangible element is a glass disc.
 20. The method of claim 16, wherein the activation component is a burst disc.
 21. The method of claim 16, wherein the first frangible element is disposed on a beveled seat in the tubular housing.
 22. The method of claim 16, further comprising: causing the fluid under the pressure to flow through a first fluid passageway of first support media in physical contact with the first frangible element, wherein the first fluid passageway is aligned with the first orifice, and wherein the fluid disintegrates the first support media until the first support media is flushed downhole by the fluid; and after the first support media is removed, flushing the first frangible element downhole by the fluid, wherein the tubular housing is fully opened to enable the fluid communication through the tubular housing.
 23. The method of claim 22, wherein the first support media is housed in a first tapered cavity in the tubular housing, and wherein the first support media is correspondingly tapered to the first tapered cavity to enable detention of the first support media in the first tapered cavity.
 24. The method of claim 16, further comprising: causing the fluid under the pressure to impact a second frangible element in physical contact with the first frangible element, wherein the fluid impacts the second frangible element at the location of the first orifice, and wherein the fluid disintegrates the second frangible element until the second frangible element is flushed downhole by the fluid; and after the second frangible element is removed, flushing the first frangible element downhole by the fluid, wherein the tubular housing is fully opened to enable the fluid communication through the subterranean wellbore.
 25. The method of claim 24, wherein the second frangible element includes a second orifice that extends partially through the second frangible element, wherein the second orifice is aligned with the first orifice.
 26. The method of claim 24, wherein the second frangible element is a glass disc seated on a beveled seat formed in the tubular housing.
 27. The method of claim 23, further comprising: causing the fluid under the pressure to flow through a second fluid passageway of second support media in physical contact with the first support media, wherein the second fluid passageway is in fluid communication with the first fluid passageway; upon the fluid under the pressure flowing through the second fluid passageway, subjecting a second orifice extending partially through a second frangible element to the pressure from the fluid, wherein the second frangible element is shattered and flushed downhole by the fluid; responsive to the second frangible element being shattered, causing the fluid under pressure to disintegrate the second support media and the first support media until the second support media and the first support media are flushed downhole by the fluid; and after the second support media and the first support media are removed, flushing the first frangible element downhole by the fluid, wherein the tubular housing is fully opened to enable the fluid communication through the subterranean wellbore.
 28. The method of claim 27, wherein the second support media is housed in a second tapered cavity in the tubular housing, wherein the second support media is correspondingly tapered to the second tapered cavity to enable detention of the second support media in the second tapered cavity, and wherein the second tapered cavity is tapered in an opposite orientation to the first tapered cavity. 